Booster actuator

ABSTRACT

A booster actuator  10  may be positioned between the solenoid  12  and a valve  14,  and increases the energy output from the solenoid to activate the valve. The booster actuator  10  may include a force input member  28  and a force output member  30  each linearly movable with respect to a body  20  from an initial position to an activated position. A coil spring  46  biases the input member to the initial input position, while a plurality of disk springs  48  bias the output member  30  to the activated output position. A plurality of linking members  32  each pivotable with respect to the body normally retain the force output member in the initial position, but upon movement of the input member to the activated position release the force output member in response to the disk springs.

FIELD OF THE INVENTION

[0001] The present invention relates to devices intended to be actuatedby a low energy input, and which output a high energy to the device tobe actuated. More particularly, the present invention relates to abooster actuator which uses mechanically stored energy to move anactuator shaft with a force and stroke sufficient to actuate varioustypes of devices.

BACKGROUND OF THE INVENTION

[0002] Those involved in system designs have long required devices whichprovide a boost or energy level increase to actuate a device. Electricenergy input to a solenoid is directly proportional to the output force,which practically limits the use of solenoids in conventional low powerelectrical systems. A relatively small and inexpensive electricalsolenoid may send a signal which will stroke a solenoid plunger,although the force and/or the stroke of the plunger in many cases isinsufficient to activate the device intended. Accordingly, boosters havebeen used between such low energy products, such as solenoids, and adevice to be activated to provide the desired energy level to actuatethe intended device.

[0003] In the fire safety industry, various systems have been devised sothat pressurized gas maybe released when a device is manually orautomatically actuated. In some applications, a booster or boosteractuator may be positioned between a solenoid and a valve, with thatvalve in turn being actuated to release agents, such as CO₂ or a mixtureof nitrogen, argon, and carbon dioxide, into the hazard area.

[0004] Prior art booster actuators have used magnetized components tohold the actuator in the set or armed position. Many of these actuatorsrequire an input force proportional to the desired output force, orrequire additional electrical circuitry to return the actuator to theset position.

[0005] Prior art actuators also include pressurized gas cartridges whichare punctured, so that the release of the pressurized gas in response tothe puncture may be used to activate a pneumatic device which releasesthe agent gas to the hazard area. Other types of actuators utilizeexplosive components to generate the increased energy to activate avalve or otherwise release the agent gas to the hazard area.

[0006] Many prior art boost devices have significant disadvantages whichhave limited their use. Prior art boost devices are relatively complexand/or are not highly reliable, and other devices cannot be easilyreset. In still other booster devices, it is difficult to vary the forcewhich activates the boost device and/or to vary the output force fromthe boost device. The disadvantages of the prior art are overcome by thepresent invention, and an improved booster actuator is hereinafterdisclosed.

SUMMARY OF THE INVENTION

[0007] In a typical application, the booster actuator of the presentinvention may be located between a solenoid and a valve. The actuatorbody houses a cam shaft or force input member which is biased by a coilspring to the initial input position. The body also houses an actuatorshaft or force output member which is biased to the activated outputposition by a plurality of disk springs. A plurality ofcircumferentially spaced links engage the force input member at one endand the force output member at the other end, and control of the releaseof the force from the disk springs to the output member in response tomovement of the cam shaft. In another embodiment, an electrical coil isprovided about the cam shaft, so that a combination solenoid and boosteris provided.

[0008] It is an object of the present invention to provide a boosterapparatus with a force input member and a force output member eachmovable relative to the actuator body, a biasing member for biasing theforce output member to the activated output position and at least onelinking member between the force input member and the force outputmember and pivotably movable with respect to the body from the engagedposition to a disengaged position for releasing the force output memberto the activated output position in response to the biasing member. Thelinking member engages both the force input member and force outputmember, and may cooperate with recesses in the input member and outputmember for achieving the desired function.

[0009] It is another feature of the invention to provide a boosteractuator with a force input member, a low force biasing member forexerting a biasing force on the input member, a force output member,another biasing member for exerting a high biasing force on the forceoutput member, and a linking member between the force input member andforce output member. Control of the actuator may be reliably obtained byproviding two biasing members each of which exert a force independent ofthe other biasing member on the input member or output member.

[0010] It is a feature of the present invention to provide a boosteractuator wherein the output force from the actuator may be easilyrevised without redesigning the remainder of the actuator. Moreover, thechange in the output force is independent of the energy required totrigger activation of the booster, and the input energy required totrigger the actuator may be separately selected without regard to theoutput requirements from the actuator.

[0011] It is another feature of the invention that the booster actuatoris highly reliable, and may be mechanically reset without the use ofelectrical devices. The reset may be accomplished quickly and easily,and no replacement of parts is necessary.

[0012] It is a further feature of the invention to provide a boosteractuator wherein a solenoid coil is provided to control movement of theforce input member relative to the actuator body.

[0013] It is an advantage of the present invention that the boosterapparatus is highly reliable and may be economically manufactured. Thebooster body preferably seals the internal components from theenvironment.

[0014] These and further objects, features, and advantages of thepresent invention will become apparent from the following detaileddescription, wherein reference is made to the figures in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a simplified cross-sectional view of a booster actuatoraccording to the present invention positioned between an electricallyactivated solenoid and a valve which is connected to a pressurized gassystem.

[0016]FIG. 2 is a cross-sectional view of a booster actuator generallyshown in FIG. 1. An internal portion of the body has been removed forclarity of the illustrated components.

[0017]FIG. 3 is a cross-sectional view of the body generally shown inFIG. 2.

[0018]FIG. 4 is another cross-sectional view of the body, illustratingthe spaced apart guides for receiving each of the four linking members.

[0019]FIG. 5 is a side view of a suitable booster reset device.

[0020]FIG. 6 is a side view of a portion of an alternate embodiment,with an electrical coil surrounding the cam shaft.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] Referring to FIG. 1, the booster actuator 10 may be threadedlysecured at one end to the body of a solenoid 12 or another electricallyactuated device, and may be similarly connected at its opposed end to avalve 14, with the valve 14 intended to release gas to an area inresponse to a sensed hazardous condition. The booster apparatus thus maybe used in conjunction with a relatively low energy electrical systemwhich monitors the surrounding environment, and outputs an electricalsignal to actuate the solenoid 12 in response to the sensed condition torelease a selected gas, e.g., for extinguishing a fire. As shown in FIG.1, the solenoid 12 includes a plunger 13 which is movable relative tothe body 20 of the booster actuator 10. The actuator 10 receives thislow energy input and outputs a high energy to control plunger 15 of thevalve 14, thereby activating the valve 14 to release the compressed gasto the environment.

[0022] The actuator 10 as shown in FIG. 2 includes a body 20 having aforce receiving input end 22 and a force delivery output end 24. Outersleeve 25 may be provided for engagement with conventional seals 26 toseal the interior of the body. The cam shaft or force input member 28 ismovable relative to the body from an initial input position as shown inFIG. 2 to an activated output position in response to movement of thesolenoid plunger. The force output member 30 is similarly movablerelative to the body from the initial output position as shown in FIG. 2to an activated output position. Four links 32 are equally spaced at 90°intervals about both the force input member and the force output member,and are each pivotable about the pin 34 which is supported on the body20. The coil spring 46 biases the force input member to the initialinput position, and a plurality of disk springs, such as disk springs48, bias the output member 30 to the activated output position.

[0023] The force input member 28 is sealed with the body by aconventional O-ring 50, and in the initial input position is biased bythe coil spring 46 to engage shoulder 52 on the body. Input member 28includes an annular recess 54 for receiving the upper end of each of thelinking members 32 when in the disengaged position, thereby allowingrelease of the force output member 30 normally held in the initialposition by the lower end of each linking member. As indicated in FIG.2, an upper roller 56 may be provided at the upper end of each link 32,and a similar roller 58 may be provided at the lower end of each link.When the actuator is in the initial position, each of the upper rollersthus engages the cylindrical exterior surface 64 of the input member 28,while each lower roller 58 fits at least partially within annular recess66 in the force output member 30. Each roller is rotatably mounted on alink with a respective pin 60 which is fixed to the link, and each linkitself is pivotable about pin 34 which is supported on the actuator body20. The position of the input member 28 thus retains each of the fourlinks in the position as shown in FIG. 2, which in turn preventsdownward movement of the force output member 30 in response to the disksprings 48.

[0024] A stop plate 62 has a central aperture therein sized to receiveplunger 68 of the force output device 30, with the stop plate beinginterconnected with the body by threads 70. Conventional ports 72 may beprovided in the stop plate for receiving a suitable tool to thread thestop plate in place, with the final position of the stop plate restingagainst snap ring 74. An O-ring 76 is held in position within the stopplate by a combination back-up ring and retaining ring 78, and providessealing engagement between the plunger 68 and the stop plate 62.

[0025] It is a particular feature of the invention that the forcerequired to move the input member 28 may be easily adjusted by varyingthe selection of the coil spring 46. The coil spring is sized so thatthe booster actuator will not inadvertently activate in response tovibration, jarring, and other forces commonly transmitted to a system.The selection of the number of coils and the material for the coils forthe spring 46 are independent, however, of the selection of the biasingmember 48, which preferably is a plurality of disk springs. The numberof disk springs and the orientation of these springs with respect toeach other affect the force and the stroke which will move the forceoutput member to the activated position, thereby extending the plungerfrom the stop plate and, in an exemplary application, actuating thevalve as shown in FIG. 1. For this exemplary embodiment, it should beunderstood that the force output member may move from the initialposition as shown in FIG. 2 to a position wherein the surface 81 engagesthe snap ring 74. This movement of the force output member 30 to theactivated output position thus results when each of the rollers 58 movesout of engagement with the recess 66, so that each of the rollers 58rolls out of the recess and into engagement with the cylindrical surface67 on force output member 30. At the same time, upper rollers 56 rollout of engagement with the cylindrical surface 64 in the force inputmember and roll partially at least within the annular recess 54 sized toreceive these rollers. This action thus causes pivoting of the links 32to release the force output member to the activated position.

[0026]FIG. 3 shows in greater detail the construction of a suitableactuator body 20, and particularly the cavity 80 for receiving the disksprings 48. The uppermost disk spring as shown in FIG. 2 thus restsagainst the surface 82 as shown in FIG. 3. FIGS. 3 and 4 also depictfour pairs of circumferentially spaced guide plates 86 and 88, therebyproviding a slot 90 therebetween for receiving a suitable link 32. FIG.4 also depicts the aligned throughports 92 in each pair of guide platesfor receiving a suitable link pin 34. The lower flange 94 of the body 20may have a suitable exterior configuration, such as a hex configuration,for engagement with a conventional tool to facilitate threadablyconnecting the body 20 to a solenoid.

[0027] It is a feature of the invention that the interior of the body 20and thus each of the movable components within the body is sealed fromthe surrounding environment, with this objective being accomplished bythe conventional seals 26 which seal between sleeve 25 and the body, andby the seals 50 and 76 which seal with the force input member and theforce output member, respectively. A sufficient seal may be createdbetween the body 20 and the stop plate 62 due to interference of thethreads although, if desired, another O-ring seal could be provided forsealing between the stop plate and the body.

[0028] In preferred embodiments, at least three linking members arecircumferentially arranged about the force input member and the forceoutput member. Three linking members at 120° interval spacing providehigh reliability by distributing the applied forces equally about theinput member and the output member. A preferred embodiment as shown inthe figures utilizes four linking members spaced at 90° intervals. Therollers 56 and 58 provided at the end of the linking members reducefrictional forces when the linking members are moved from an engagedposition as shown in FIG. 2 for retaining the force output member 30 inthe initial output position to a disengaged position which releases theforce output member to the activated output position. In alternateembodiments, the rollers may be eliminated, or may be replaced withother conventional members intended to reduce friction with the forceinput and force output members.

[0029] Coil spring 46 acts between the force output member 30 and theforce input member 28. The force of this spring may be easily alteredwithout modifying other components of the booster actuator in order tochange the force required to activate the booster 10. Similarly, thesize, orientation, and number of disk springs 48 may be altered toeffect the stroke length and/or the force which will be output by theplunger 68 when moved to the activated output position. Alternativetypes of springs or other biasing members may be utilized.

[0030] The booster actuator of the present invention provides amechanical separation of the input member and the output member. Thecoil spring 46 biases the input member to the initial position, but thisexerts a small force on the output member compared to the bias of thesprings 48. By providing no direct mechanical connection between theinput member and the output member, the reactive forces on the valvewhich are transmitted back to the force output member during actuationof the booster are prevented from being transmitted to the force inputmember and then to the solenoid. The coil spring thus isolates thereactive force on the output member from the forces applied to the inputmember, and a latching solenoid mechanism may thus be used to activatethe booster without fear of damage from these reactive forces.

[0031] Once the booster is activated, the booster may be easily resetwithout use of electrical devices, and without replacement of parts.After the valve 14 has been removed from the booster body, reset device94 as shown in FIG. 5 may be connected to the threads 70 on the body.After the reset outer body 96 bottoms out against the stop plate 62, thebolt 98 may be rotated relative to outer body 96 to project the tip 97toward the stop plate 62. The tip 97 is thereby forced into engagementwith the end of the plunger 68, thereby forcing the force output member30 back to the initial position as shown in FIG. 2. The return of theforce output member to the initial position also increases the force onthe coil spring to return the force input member to the initialposition.

[0032]FIG. 6 depicts another embodiment of the invention, wherein acombination solenoid and booster actuator is provided. That portion ofthe booster 10 to the right of the force input member 128 may be asdescribed above. In this embodiment, however, an extension of the forceinput member is provided so that the extended length force input member128 is positioned within a solenoid coil 114. The solenoid coil may alsobe referred to as a magnetic latch subassembly, which receiveselectrical power to selectively move the input member 128. Those skilledin the art will appreciate that an extended length force input membermay be used, as shown, or a two-piece or multi-piece mechanicalinterconnection made between the solenoid plunger and the force inputmember. Activation of the coil 114 thus initiates movement of thesolenoid plunger, which in this case is the force input member 128.Force input member 128 includes a stop 130 for engagement with thesurface 132 to limit the travel of the force input member. FIG. 6depicts sleeve 134 enclosing the solenoid 114, and body 136 whichconnects sleeve 134 with sleeve 25.

[0033] While a preferred embodiment of the present invention has beenillustrated in detail, it is apparent that modifications and adaptationsof the proposed embodiment will occur to those skilled in the art.However, it is to be expressly understood that such modifications andadaptations are within the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A booster actuator for receiving a low energyinput and outputting a high energy output to operate a device, thebooster comprising: a body having a force receiving input end and forcedelivery output end; a force input member movable relative to the bodyin response to the low energy force input from an initial input positionto an activated input position; a force output member movable relativeto the body in response to movement of the force input member from aninitial output position to an activated output position; a biasingmember for biasing the force output member to the activated outputposition; and a linking member between the force input member and theforce output member and pivotally movable with respect to the body froman engaged position for retaining the force output member in the initialoutput position to a disengaged position for releasing the force outputmember to the activated output position, the linking member having aninput end engaging the force input member and an output end engaging theforce output member.
 2. The booster actuator as defined in claim 1,further comprising: another biasing member for biasing the force inputmember to the initial input position.
 3. The booster actuator as definedin claim 1, wherein the force output member includes an output memberrecess for receiving a lower end of the linking member when in theengaged position.
 4. The booster actuator as defined in claim 3, whereinthe force input member includes an input member recess for receiving anupper end of the linking member when in the disengaged position, therebyallowing disengagement of the lower end of the linking member from theoutput member recess.
 5. The booster actuator as defined in claim 1,wherein at least three linking members each pivotable with respect tothe body are circumferentially arranged about the force input member andthe force output member.
 6. The booster actuator as defined in claim 5,wherein four linking members are spaced circumferentially atapproximately 90° intervals about the force input member and forceoutput member.
 7. The booster actuator as defined in claim 1, furthercomprising: the biasing member comprises a plurality of disk springs;and another biasing member for biasing the force input member to theinitial input position.
 8. The booster actuator as defined in claim 1,further comprising: an electrical coil surrounding the force inputmember, such that a change in electrical energy to the coil moves theforce input member to the activated input position.
 9. The boosteractuator as defined in claim 1, wherein each of the input end and outputend of the linking member is provided with a roller for engaging theforce input member and the force output member, respectively.
 10. Thebooster actuator as defined in claim 1, wherein the force deliveryoutput end of the body includes threads, and a reset member threaded tothe delivery output end is rotated relative to the body to forceablyengage the force output member to move the force output member from theactivated position to the initial position.
 11. A booster actuator forreceiving a low energy force and outputting a high energy force outputto operate another device, the booster comprising: a body having a forcereceiving input end and force delivery output end; a force input memberlinearly movable relative to the body in response to the low energyforce input from an initial input position to an activated inputposition; a first biasing member for biasing the force input member tothe initial input position; a force output member linearly movablerelative to the body in response to movement of the force input memberfrom an initial output position to an activated output position; asecond biasing member for biasing the force output member to theactivated output position; and a linking member between the force inputmember and the force output member and movable from an engaged positionfor retaining the force output member in the initial output position toa disengaged position for releasing the force output member to theactivated output position.
 12. The booster actuator as defined in claim11, wherein at least three linking members each pivotable with respectto the body are circumferentially arranged about the force input memberand the force output member.
 13. The booster actuator as defined inclaim 11, wherein the first biasing member is a coil spring, and thesecond biasing member comprises a plurality of disk springs.
 14. Thebooster actuator as defined in claim 11, further comprising: anelectrical coil surrounding the force input member, such that a changein electrical energy to the coil moves the force input member to theactivated input position.
 15. The booster actuator as defined in claim11, wherein each of the input end and output end of the linking memberis provided with a roller for engaging the force input member and forceoutput member, respectively.
 16. A booster actuator for receiving a lowenergy input from an electrically activated device and outputting a highenergy to activate a release of pressurized gas to a hazard area, thebooster comprising: a body having a force receiving input end and forcedelivery output end; a force input member linearly movable relative tothe body in response to the low energy force input from an initial inputposition to an activated input position; a force output member linearlymovable relative to the body in response to movement of the force inputmember from an initial output position to an activated output position;a first biasing member for biasing the force output member to theactivated output position; a second biasing member for biasing theoutput force member to the activated output position; a plurality oflinking members each between the force input member and the force outputmember and pivotally movable relative to the body from an engagedposition for retaining the force output member in the initial outputposition to a disengaged position for releasing the force output memberto the activated output position, the linking members beingcircumferentially arranged about the force input member and the forceoutput member and each having an input end engaging the force inputmember and an output end engaging the force output member; and the forceoutput member includes an output member recess for receiving a lower endof each of the linking members when in the engaged position.
 17. Thebooster actuator as defined in claim 16, wherein the force input memberincludes an input member recess for receiving an upper end of thelinking member when in the disengaged position, thereby allowingdisengagement of the lower end of the linking member from the outputmember recess.
 18. The booster actuator as defined in claim 16, whereina central axis of the force input member is substantially aligned with acentral axis of the force output member.
 19. The booster actuator asdefined in claim 16, further comprising: the second biasing membercomprises a plurality of disk springs.
 20. The booster actuator asdefined in claim 16, wherein the force delivery output end of the bodyincludes threads, and a reset member threaded to the delivery output endis rotated relative to the body to engage the force output member tomove the force output member from the activated position to the initialposition.